Interventions for preventing high altitude illness: Part 3. Miscellaneous and non-pharmacological interventions

Franco, Daniel; Estrada, Víctor; Garay, Alejandro G Gonzalez; Martí‐Carvajal, Arturo J; Arévalo-Rodríguez, Ingrid

doi:10.1002/14651858.cd013315

Cited by 12 publications

(9 citation statements)

References 136 publications

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“…Beidleman et all reported that staging at 2200 m for 6 days before ascending to 4300 m reduced the incidence and severity of AMS 21 . Although a 2019 Cochrane review reported that the effect of preacclimatisation strategies on improving the risk of AMS as uncertain, it is still sensible recommending gradual ascent according to the results of the studies and extensive clinical experiences 22 . Travelers are recommended to spend 6–7 days at moderate altitude like 2200–3000 m before proceeding higher altitude.…”

Section: Preventionmentioning

confidence: 99%

High-altitude illness: Management approach

Aksel

Çorbacıoğlu

Özen

2019

Turkish Journal of Emergency Medicine

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In high altitudes, usually above 2500 m, travelers are faced with decreased partial pressure of oxygen along with decreased barometric pressure. High-altitude illness, a syndrome of acute mountain sickness, high-altitude cerebral edema and high-altitude pulmonary edema, occurs due to the hypobaric hypoxia when there is inadequate acclimatization.This review provides detailed information about pathophysiology, clinical features, prevention and treatment strategies for high-altitude illness according to the current literature.

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Section: Preventionmentioning

confidence: 99%

High-altitude illness: Management approach

Aksel

Çorbacıoğlu

Özen

2019

Turkish Journal of Emergency Medicine

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Section: Introductionmentioning

confidence: 99%

“…Some pharmacological interventions (e.g., acetazolamide) have been shown to reduce AMS symptoms [10,11]. However, a recent Cochrane review concluded that there is currently no clear evidence for any nonpharmacological intervention to robustly mitigate AMS [12]. Interestingly, early studies in rodents observed that increasing ketone bodies (KB) in the blood improved tolerance to extreme hypoxia (FIO2: 4-5%) [13,14].…”

Section: Introductionmentioning

confidence: 99%

Exogenous ketosis attenuates acute mountain sickness and mitigates high-altitude hypoxemia

Stalmans,

Tominec,

Lauriks

et al. 2023

Preprint

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BackgroundAcute mountain sickness (AMS) represents a considerable issue for individuals sojourning to high altitudes with systemic hypoxemia known to be intimately involved in its development. Based on recent evidence that ketone ester (KE) intake attenuates hypoxemia, we sought to investigate whether exogenous ketosis might mitigate AMS development and improve hypoxic tolerance.MethodsFourteen healthy, male participants were enrolled in two 29h protocols (simulated altitude of 4,000-4,500m) receiving either KE or a placebo (CON) at regular timepoints throughout the protocol in a randomized, crossover manner. Select physiological responses were characterized after 15min and 4h in hypoxia, and the protocol was terminated prematurely upon development of severe AMS.ResultsAll participants tolerated the protocol equally long (n=6, of which n=5 completed the protocol in both conditions) or longer (n=8) in KE. Overall protocol duration increased by 32% on average with KE, and doubled for AMS-developing participants. KE consistently induced diurnal ketosis, a mild metabolic acidosis, hyperventilation, and relative sympathetic dominance. KE also fully negated the progressive hypoxemia that was observed between 15min and 4h in hypoxia in CON, while concomitantly increasing cerebral oxygenation and capillary pO2within this timeframe. This coincided with a KE-induced reduction in cerebral oxygen supply, suggesting that KE reduced cerebral oxygen consumption under hypoxic conditions.ConclusionsThese data indicate that exogenous ketosis improves hypoxic tolerance in humans and attenuates AMS development. The key underlying mechanisms include improved arterial and cerebral oxygenation, in combination with lowered cerebral blood flow and oxygen demand, and increased sympathetic dominance.SummaryKetone ester intake attenuated the development of acute mountain sickness at a simulated altitude of 4,000-4,500m. This likely resulted from a mitigation of arterial and cerebral hypoxemia, reduced cerebral blood flow and increased sympathetic drive.

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“…The Wilderness Medical Society has released recommendations for the prevention of AMS, including gradual ascent and taking acetazolamide and/or dexamethasone (Luks et al, 2019). However, some persons do not ascend gradually, and some cannot tolerate the side effects of the drugs, although intolerance to acetazolamide is rare; therefore, new nonpharmacological approaches still need to be explored (Bartsch & Swenson, 2013; Molano Franco, Nieto Estrada, Gonzalez Garay, Marti‐Carvajal, & Arevalo‐Rodriguez, 2019).…”

Section: Introductionmentioning

confidence: 99%

Repeated remote ischaemic preconditioning can prevent acute mountain sickness after rapid ascent to a high altitude

Wang

Zhang

et al. 2021

European Journal of Sport Science

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Background:The aim of the present study was to assess the effectiveness of 4 different remote ischaemic preconditioning (RIPC) protocols varying in duration and frequency for preventing acute mountain sickness (AMS). Methods: The participants in the four RIPC groups received different RIPC treatments in the arms at a low altitude; the control group did not receive a specific sham treatment. The participants were then flown to a High Altitude (3650 m). The primary outcome was the incidence and severity of AMS evaluated by the Lake Louise score (LLS) after arrival; vital signs were collected simultaneously. We performed an intention-to-treat analysis. Results: A total of 250 participants were included with 50 participants in each group. The total AMS incidence in all participants was 26.4%. A total of 20 AMS cases (40%) occurred in the control group, whereas 15 AMS cases (30%) occurred both in the RIPC A and RIPC B groups (relative risk 1.3; 95% confidence interval 0.8 -2.3; χ2 = 1.099; p = 0.29), and 8 AMS cases (16%) occurred both in the RIPC C and D groups (RR 2.5; 95% CI 1.2 -5.2; χ2 = 7.143, p < 0.01), with significantly lower LLSs in the RIPC C and D groups (F = 6.51, p <0.001). Conclusion: This study demonstrated that a four-week RIPC intervention but not a one-week regimen reduced AMS incidence and severity; however, a placebo effect might have contributed to the results of this study. Methods: The participants in the four RIPC groups received different RIPC treatments in the arms at a low altitude; the control group did not receive a specific sham treatment. The participants were then flown to a High Altitude (3650 m). The primary outcome was the incidence and severity of AMS evaluated by the Lake Louise score (LLS) after arrival; vital signs were collected simultaneously. We performed an intention-to-treat analysis. Results: A total of 250 participants were included with 50 participants in each group. The total AMS incidence in all participants was 26.4%. A total of 20 AMS cases (40%) occurred in the control group after arrival at high altitude, whereas 15 AMS cases (30%) occurred both in the RIPC A and RIPC B groups (relative risk 1.3; 95% confidence interval 0.8 -2.3; χ 2 = 1.099; p = 0.29), and 8 AMS cases (16%) occurred both in the RIPC C and D groups (RR 2.5; 95% CI 1.2 -5.2; χ 2 = 7.143, p < 0.01), with significantly lower LLSs in the RIPC C and D groups (F = 6.51, p <0.001). Conclusion:This study demonstrated that a four-week RIPC intervention but not a one-week regimen reduced AMS incidence and severity; however, a placebo effect might have contributed to the results of this study.

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Interventions for preventing high altitude illness: Part 3. Miscellaneous and non-pharmacological interventions

Abstract: Analysis 2.2. Comparison 2 Group 2. Ginkgo biloba versus placebo, Outcome 2 Risk of high altitude pulmonary oedema........... Analysis 2.3. Comparison 2 Group 2. Ginkgo biloba versus placebo, Outcome 3 Risk of high altitude cerebral oedema.

Cited by 12 publications

References 136 publications

High-altitude illness: Management approach

High-altitude illness: Management approach

Exogenous ketosis attenuates acute mountain sickness and mitigates high-altitude hypoxemia

Repeated remote ischaemic preconditioning can prevent acute mountain sickness after rapid ascent to a high altitude

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